“Aegeline is a normal component of the Bael tree, and it’s been used as a natural product by naturopathic healers for centuries, usually fairly safely,” Dr Bonkovsky said.

“But they didn’t use Bael tree extract. They bought aegeline from a Chinese drug company that made aegeline, at least, the company claimed it was aegeline, and within a few months, they began to observe patients with liver failure, mostly in Hawaii but not entirely.”

This means manufacturers need only certify they have used pre-approved ingredients and that the product has been made according to good manufacturing practice standards.

So for “low risk” products, the TGA relies on the honesty of the manufacturer, when it comes to establishing ingredient quality and the manufacturing process.

Supplements purchased online, especially from international suppliers, or in the form of teas are not subject to TGA regulations, and consumers have no guarantee about the safety or effectiveness of these products.

You can watch the story on this special report on Four Corners at 8:30pm on ABC TV.